Sporophyte

Sporophyte, which literally means "spore-bearing" plant, is the diploid multicellular phase of an organism that displays alternation of generations. The sporophyte phase develops from the fertilized egg, or zygote, by simple cell division and subsequent differentiation. Sporophytes occur in a few algae and aquatic fungi, and are universal in true plants. They differ greatly in size and level of complexity. In bryophytes the sporophyte is short-lived and permanently attached to the female parent, upon which it is nutritionally dependent. In all other plants, the sporophyte becomes independent of the female parent soon after embryological development is completed and remains as the dominant, photosynthetic stage of the plant. In the simplest case, a sporophyte can consist of only a capsule, or sporangium, as in the liverwort Riccia, but usually it will also possess one or more vegetative organs. For example, in mosses the sporophyte consists of a foot; a green, stemlike seta ; and a single complex sporangium, while in pines it is a highly branched tree with roots, stems, leaves and thousands of sporangia. Within the sporangia, which are the reproductive organs of the sporophyte, haploid spores are produced by meiosis . Germination of these spores marks the beginning of the haploid, sexual phase of the life cycle.

see also Bryophytes; Gametophyte; Reproduction, Alternation of Generations and; Reproduction, Asexual; Reproduction; Sexual.

Barbara Crandall-Stotler

Bibliography

Graham, Linda. "The Origin of the Life Cycle of Land Plants." American Scientist 73 (1985): 178-86.

sporophyte Diploid stage in the life cycle of a plant or alga. Usually, the sporophyte gives rise to haploid spores which germinate to produce a haploid generation (the gametophyte stage) that will produce the gametes. In ferns, horsetails, conifers and angiosperms, the diploid sporophyte is the dominant phase of the life cycle, the plant body we usually see. In mosses and liverworts, the main plant body is the gametophyte. See also alternation of generations

spo·ro·phyte / ˈspôrəˌfīt/ • n. Bot. (in the life cycle of plants with alternating generations) the asexual and usually diploid phase, producing spores from which the gametophyte arises. It is the dominant form in vascular plants, e.g., the frond of a fern. DERIVATIVES: spo·ro·phyt·ic / ˌspôrəˈfitik/ adj.

sporophyte The spore-producing diploid generation in the life cycle of plants. In higher plants, such as angiosperms and gymnosperms, the sporophyte is the dominant generation, forming the conspicuous plant. In lower plants, such as mosses, liverworts, ferns, and fungi, the gametophyte is the dominant and conspicuous generation. See also ALTERNATION OF GENERATIONS.

sporophyte The generation in the life cycle of a plant that produces spores. The sporophyte is diploid but its spores are haploid. It is either completely or partially dependent on the gametophyte generation in mosses and liverworts, but is the dominant plant in the life cycle of clubmosses, horsetails, ferns, and seed plants. See also alternation of generations.

sporophyte The spore-producingdiploid generation in the life cycle of plants. In higher plants, such as angiosperms and gymnosperms, the sporophyte is the dominant generation, forming the conspicuous plant. In lower plants, such as mosses, liverworts, and ferns, the gametophyte is the dominant and conspicuous generation. See also alternation of generations.

sporophyte: see gametophyte.